FraMCoS 5 2004 Vail, Colorado, USA

Double-K Parameters and the Cohesive-Stress-Based KR Curve for the Negative Geometry

In this paper, the fictitious crack distributed with softening cohesive stress in the case of the infinite plate with a semi-infinite crack, as an example of negative facture geometry was analytically solved and numerically studied. Using the analytical solutions and…

First page of: Double-K Parameters and the Cohesive-Stress-Based KR Curve for the Negative Geometry
Year 2004
File Size 492 KB
Download PDF (492 KB)

Abstract

In this paper, the fictitious crack distributed with softening cohesive stress in the case of the infinite plate with a semi-infinite crack, as an example of negative facture geometry was analytically solved and numerically studied. Using the analytical solutions and numerical results both double-K parameters and cohesive stress based K curve were determined. The gained results show that there exist crack initiation, R crack propagation until maximum load was exceeded and the crack retrenches slowly after maximum load. The three-parameter law of fracture toughness increase exists yet in such negative geometry. Therefore, the double-K fracture model applies to the negative geometry too. The net stress intensity factor at the propagating crack tip is larger than 60% of the total stress intensity factor caused by the externally applied load. It implies that a zero net stress intensity factor at the fictitious crack tip does not exist in the case of negative geometry.